The invention relates to an optical deflecting device.
It is known to provide optical deflecting devices in which a first optical sub-unit for deflecting a light beam, a second optical sub-unit for deflecting a light beam, and an optical bridge between the optical exit axis of the first optical sub-unit and the optical entrance axis of the second optical sub-unit, the axes being parallel with one another and, starting from reference positions of the sub-units about their respective axes, relative to the optical bridge, the angle of the first optical sub-unit, about its optical exit axis, being equal to the angle of the second optical sub-unit, about its optical entrance axis.
An optical deflecting device of this type has, for example, been disclosed in German Offenlegungsschrift No. 2,502,209. The known device is integrated into a binocular tube of an optical observation instrument in order to prevent rotation of the image when the tube is moved relative to the stationary body of the optical observation instrument, this image-rotation normally occurring as the eyepiece tubes are moved. In the known device, the optical sub-units, which take the form of split-cube prisms, are, in the imaginary datum position, aligned in a manner such that the optical entrance axis of the first optical sub-unit extends along the same line as the optical exit axis of the second optical sub-unit, but in the opposite direction, and the optical bridge comprises a split-cube prism and a pentagonal prism possessing a top edge so that an image is rotated once through 180.degree.. By this means the observer does not see the object under observation inverted, which, in the case of a microscope, makes it difficult to handle the object under observation.
If the known optical deflecting device is to be used in order to project an erect and laterally non-reversed image onto a projection screen which is parallel to the object carrier, this image being extracted from a microscope by, for example, a reflecting system, it is necessary to couple further split-cube prisms to the second split-cube prism, and this is expensive.